1. Field of the Invention
The present invention relates to a novel solid form of 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one, to a process for preparing this novel solid form and to its advantageous use for preparing stable use forms.
2. Description of Related Art
The compound 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one and methods for preparing this compound are known. It is also known that this compound has insecticidal and acaricidal action. Thus, for example, WO 2007/115644 describes for the first time the preparation of this compound and its use for controlling arthropods, in particular insects. Furthermore, the preparation of this compound has been described in WO2009/036899. It has now been found that the compound prepared by the known processes cannot be used in an economically relevant form, since the compound prepared by these processes is present in amorphous form. This becomes evident by the fact that it is not possible to determine a melting point. Melting points are always present if there is a long-range order, especially if a crystalline structure is present. Likewise, as can be seen from FIG. 1a, it is not possible to obtain a resolved X-ray powder diffractogram.
In particular, it is a disadvantage that the compound is highly viscous in the amorphous state and can therefore not be converted into formulations in which the active compound is present in solid (dry) form. Such economically important formulations are, for example, granules, encapsulated granules, tablets, water-dispersible granules, water-dispersible tablets, water-dispersible powders or water-dispersible powders for the treatment of seed, dust formulations, formulations in which the active compound is present in dispersed form, such as, for example: suspension concentrates, oil-based suspension concentrates, suspoemulsions or suspension concentrates for the treatment of seed. Formulations are of economical relevance, for example, when the active compounds to be used are particularly suitable for preparing formulations requiring the use of grinding processes, and/or when such formulations have good storage stability.